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United States Patent |
5,791,338
|
Merchant
,   et al.
|
August 11, 1998
|
Endotracheal intubation apparatus
Abstract
A tool assists in placing an endotracheal tube into the trachea of a
patient by controllable diverting of the end of the tube. A tool with at
least one endmost link that can be manually diverted exclusively at the
distal end using a lever handle, is placed in the tube. A proximal portion
of the tool adjacent the handle at least partly defines an internal
passage that can be an open channel. The proximal portion is substantially
rigid, although it can be manually bent into a desired rigid arc. At least
one distal link occupies 10-20% (4-5 cm) of the tool length and is
attached to the proximal portion by a pivot pin permitting the distal link
to pivot in the medial plane of the patient. The control member, namely a
rod, wire or the like, passes anteriorly of the pivot pin relative to the
patient, and is attached to the distal link. Tension applied to the
control member diverts the end of the endotracheal tube by
90.degree.-100.degree., for guidance through the larynx. The proximal
portion is nearly as wide as the internal diameter of the endotracheal
tube, which diverts to substantially the same extent as the distal link.
Inventors:
|
Merchant; William T. (925 Hartman La., Lebanon, PA 17042);
Gerberich; Guy G. (Jonestown, PA)
|
Assignee:
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Merchant; William T. (Lebanon, PA)
|
Appl. No.:
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587752 |
Filed:
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January 17, 1996 |
Current U.S. Class: |
128/200.26; 128/207.14; 128/207.15 |
Intern'l Class: |
A61M 016/00 |
Field of Search: |
128/200.26,207.14,207.15,657,772
604/95,170
|
References Cited
U.S. Patent Documents
2498692 | Feb., 1950 | Mains | 128/348.
|
3060972 | Oct., 1962 | Sheldon | 138/120.
|
3416531 | Dec., 1968 | Edwards | 128/348.
|
3521620 | Jul., 1970 | Cook | 128/2.
|
3776222 | Dec., 1973 | Smiddy | 604/95.
|
3802440 | Apr., 1974 | Salem et al. | 128/772.
|
3968800 | Jul., 1976 | Vilasi | 128/207.
|
4150676 | Apr., 1979 | Jackson | 128/351.
|
4329983 | May., 1982 | Fletcher | 128/207.
|
4502482 | Mar., 1985 | DeLuccia, deceased et al. | 128/207.
|
4529400 | Jul., 1985 | Scholten | 604/95.
|
4589410 | May., 1986 | Miller | 128/207.
|
4685457 | Aug., 1987 | Donenfeld | 128/207.
|
4690138 | Sep., 1987 | Heyden | 128/207.
|
4846153 | Jul., 1989 | Berci | 128/207.
|
4886059 | Dec., 1989 | Weber | 128/207.
|
4886067 | Dec., 1989 | Palermo | 128/657.
|
4949716 | Aug., 1990 | Chenoweth | 128/207.
|
5058577 | Oct., 1991 | Six | 128/207.
|
5235970 | Aug., 1993 | Augustine | 128/207.
|
5259377 | Nov., 1993 | Schroeder | 128/207.
|
5403297 | Apr., 1995 | Imran | 128/657.
|
Primary Examiner: Lewis; Aaron J.
Attorney, Agent or Firm: Eckert Seamans Cherin & Mellott
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATION
This application is a continuation in part of application Ser. No.
08/187,609 filed Jan. 26, 1994, now abandoned.
Claims
We claim:
1. A tool for assisting in manual placement of an endotracheal tube in a
patient such that such an endotracheal tube passes through a mouth,
pharynx and larynx of the patient, the tool comprising:
an elongated proximal portion at least partly defining a fixed arc and
passage leading toward an articulating distal end of the tool, the
proximal portion being substantially rigid;
at least one articulating distal link attached to the distal end of the
proximal portion of the tool by at least one pivot pin defining a pivot
axis perpendicular to a plane occupied by the proximal portion, thereby
permitting the link to pivot relative to the proximal portion in said
plane;
an elongated control member extending along the passage and being attached
to the distal link, the control member being laterally spaced from the
pivot axis in said plane;
means for applying tension to the control member such that an articulating
distal link portion is diverted relative to the fixed arc of the
substantially rigid proximal portion toward said inner side of the pivot
axis in the plane; and,
wherein the proximal portion is substantially integrally rigid, whereby the
endotracheal tube can be diverted substantially exclusively at the link
toward said inner side to achieve said manual placement.
2. The tool according to claim 1, wherein the articulating distal link
extends only over a distal length of about 10-20% of a length of the tool.
3. The tool according to claim 1, wherein the articulating distal link
encompasses a length of about 4-5 cm of the tool.
4. The tool according to claim 1, wherein the proximal portion and the
articulating distal link comprise integral stainless steel parts.
5. The tool according to claim 1, wherein the control member comprises one
of a flexible cable or a rod extending along a channel in the proximal
portion.
6. The tool according to claim 1, wherein the proximal portion is malleable
such that the fixed arc can be changed by manual force.
7. The tool according to claim 1, wherein the means for applying tension
comprises a base at a proximal end of the proximal section and a lever
pivotally mounted on the base, the control member being attached to the
lever for application of tension to the control member, and the passage
providing lateral clearance for displacement of the control member
relative to the proximal portion.
8. The tool according to claim 1, wherein the means for applying tension
comprises a base at a proximal end of the proximal section and a lever
pivotally mounted on the base, the control member being attached to the
lever for application of tension to the control member, wherein the
proximal portion is bent in a curve in the plane.
9. A tool for assisting in manual placement of an endotracheal tube in a
patient such that such an endotracheal tube passes through a mouth,
pharynx and larynx of the patient, the tool comprising:
an elongated proximal portion at least partly defining a fixed arc and a
longitudinal passage in a plane of the proximal portion, leading from a
fixed proximal end toward an articulating distal end of the tool, the
proximal portion being substantially rigid;
at least one articulating distal link attached to the distal end of the
fixed proximal portion of the tool by a pivot pin defining a pivot axis
permitting the articulating link to pivot relative to the proximal portion
in said plane;
an elongated control member extending along the proximal portion, the
control member passing along an inner side of the pivot axis and being
attached to the articulating link; and,
means for applying tension to the control member such that the articulating
link portion is diverted toward said inner side of the pivot axis, whereby
an endotracheal tube can be placed on the tool and guided through the
larynx.
10. In combination, an endotracheal tube and a tool for assisting in manual
placement of the endotracheal tube in a patient such that the tube passes
through a mouth, pharynx and larynx of the patient, the tool comprising:
an elongated proximal portion at least partly defining a fixed arc and
passage, the proximal portion being rigidly curved in a fixed arc in a
plane of the proximal portion, leading toward an articulating distal end
of the tool, the proximal portion being substantially rigid;
an articulating distal link attached to the distal end of the proximal
portion of the tool by a pivot pin defining a pivot axis perpendicular to
the plane of the proximal portion, thereby permitting the articulating
link to pivot relative to the fixed proximal portion in said plane, the
endotracheal tube, the fixed proximal portion and the articulating link
being dimensioned such that the endotracheal tube can slide onto the tool;
an elongated control member extending through the proximal portion, the
control member passing on an inner side of the pivot axis relative to the
fixed arc and being attached to the articulating link; and,
means for applying tension to the control member such that the articulating
link portion is diverted relative to the fixed arc of the substantially
rigid proximate portion toward said inner side of the pivot axis in the
medial plane, whereby an endotracheal tube can be placed on the tool and
guided through the larynx.
11. The combination according to claim 10, wherein the substantially rigid
proximal portion and the articulating link portion has an outside diameter
equal to 50 to 90% of an internal diameter of the endotracheal tube.
12. The combination according to claim 10, wherein the proximal portion has
an outside diameter approximating an internal diameter of the endotracheal
tube, with sufficient clearance to permit free sliding of the tool in the
endotracheal tube, whereby the endotracheal tube is diverted substantially
to a same extent as the articulating link portion.
13. The combination according to claim 10, further comprising a stop
disposed on the proximal portion, the stop being placed to position the
link at a distal end of the endotracheal tube.
14. The combination according to claim 13, further comprising means for
adjusting a position of the stop and fixing the stop in said position.
15. The combination according to claim 10, wherein the articulating link
portion is operable to divert the endotracheal tube from a neutral
position aligned to the substantially fixed proximal portion to a diverted
position wherein a distal end of the endotracheal tube is divertable at
least 90.degree. from the neutral position.
16. The combination according to claim 15, wherein the articulating link
portion is operable to divert the endotracheal tube in an area of an
endmost articulating distal link to greater than 100.degree. anteriorly of
said neutral position.
17. The combination according to claim 10, wherein the substantially rigid
proximal portion defines a channel receiving the control member for
longitudinal displacement and the means for applying tension comprises a
lever handle attached to the control member and to a pivot connection with
the proximal portion, such that the control member is raised in the
channel by pivoting the lever handle.
18. The combination according to claim 10, further comprising a movable
stop on the proximal portion for setting a position of the endotracheal
tube along the tool.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to devices for assisting in oral tracheal intubation
or placement of an endotracheal tube through the mouth, and in particular
concerns an intubation guide approximating an internal diameter of the
tube, the guide having a distal tip that is articulated and manually
controlled to obtain a sharp anterior deflection at the end of the tube
for passing the tube through the larynx.
2. Prior Art
Endotracheal tubes are used to couple a patient's respiratory system to a
breathing apparatus during surgical procedures or emergency situations. A
typical endotracheal tube is made of polyvinyl chloride or the like and
has an inflatable cuff several centimeters from an end of the tube that is
inserted into the trachea, whereby the tube can be sealed relative to the
trachea by inflating the cuff through an inflation line passing along the
tube. A fitting on an opposite end of the tube couples to an artificial
respirator or ventilator.
The tube is dimensioned to provide an adequate airflow for the patient, and
may have an internal diameter of 2.0 to 9.5 mm, depending on the air flow
required, normally varying as a function of the size of the patient. A
typical internal diameter for adults is 5.5 to 8.5 mm and a typical length
is about 30 cm. The tube is somewhat flexible but must be sufficiently
rigid to ensure that the lumen of the tube does not pinch shut or become
restricted if the tube is flexed. Therefore, the tube has a substantial
wall thickness to provide necessary rigidity, e.g. 2 mm wall thickness.
The tube typically is manufactured to assume a smooth arc at rest, this
arc approximating the curve of the passage through the mouth to the
trachea. For example, from end to end the tube can define a quadrant
(90.degree.) of a circular arc with a radius of curvature of about 20 cm.
In placing the endotracheal tube, it is necessary to guide the cuffed or
distal end of the tube around an anterior bend to bring the end of the
tube forward through the larynx and into the trachea, rather than rearward
into the esophagus and the digestive system. There are various situations
in which the tube must be placed quickly, and in every case the tube must
be placed properly so as to ensure airflow. In connection with surgery
under general anesthesia, for example, a typical procedure is to render
the patient unconscious, e.g., using pentothal, and also to administer a
neuromuscular blocking agent such as succinylcholine to block involuntary
and voluntary muscular movements that may interfere with a surgical
procedure. This also stops respiration by disabling all muscles of
respiration. At this point, the endotracheal tube must be properly
positioned in a timely fashion to avoid potentially catastrophic results
from hypoxia at the brain and heart. It is obviously desirable to place
the tracheal tube properly on the first attempt.
Oral rather than nasal placement of the tracheal tube is generally
preferred. Various tools have been devised to assist in placing the tube,
i.e., threading the cuffed end through the mouth and the pharynx, turning
forward to pass the epiglottis and larynx, and advancing the tube several
centimeters into the trachea until the inflatable cuff passes the vocal
cords. Typically, a laryngoscope having a generally spoon shaped blade is
used to pull the tongue and associated tissues anteriorly (i.e., upwardly
for a supine patient). Often, this is sufficient to enable proper
placement of the endotracheal tube. Occasionally some form of tool is used
to assist in guiding the tube into place.
According to one technique, a thin malleable metal stylette is inserted
into the trachea for guiding the tracheal tube into place by sliding the
tube along the stylette. First the stylette is bent manually to
approximate an estimated path of the tracheal tube, i.e., the stylette is
curved into an arc and may be diverted or bent anteriorly at the distal
end so as to point toward the larynx when inserted orally. The length and
extent of the bend that is possible is limited by the need to pass the
stylette along the path to the trachea. The endotracheal tube is placed on
the stylette, which is inserted into the patient. The tube then is pushed
axially along the stylette, and if all goes well, into the trachea. This
approach requires correct estimation of the path and a certain dexterity,
and sometimes requires repeated attempts as the stylette is adjusted,
tried, removed and adjusted again.
The stylette has a substantially smaller diameter than the tracheal tube.
Although the stylette may traverse the larynx, the end of the tube, which
is wider, may encounter tissues and require repositioning to enable the
tube to pass. Additionally, because the stylette is thin compared to the
inside diameter of the tube, the tube does not bend to the same angle as
the stylette and instead assumes a longer radius of curvature. The
stylette is inexpensive, but it is a cumbersome, time consuming and
inefficient means to achieve a bend at the distal tip of the endotracheal
tube for guiding the tube into place.
A stylette including a mechanism for manually varying a bending arc at the
distal end of the stylette, is available from Mainline Medical, Inc.,
Smyrna, Ga., under the name Flexguide. The stylette is made of flexible
plastic, laterally slotted exclusively along one side to define a series
of articulated segments over a span of several centimeters at the distal
end portion of the stylette. A solid movable plunger extends axially
through a central passageway and is attached or abutted against a segment
at the distal end. By pulling or pushing the plunger relative to the
remainder of the stylette using a finger ring, the distal end is caused to
bend toward or away from the slotted side, respectively. Due to the
segment structure, bending occurs evenly over the span of segments, such
that it is difficult to make an abrupt bend. The stylette is also narrow
compared to the internal diameter of the endotracheal tube, making it
difficult or impossible to use the tool to alter the curve of a tube
placed on the stylette. Instead, diversion of the end of the stylette is
used to aim the end of the stylette toward the larynx, using the four or
five centimeters of tissue space in the area of the pharynx and larynx.
The stylette is placed in the trachea and the tube is pushed along the
stylette in the same manner as with a malleable metal stylette.
Other devices are known that are intended to bend the endotracheal tube
itself. In U.S. Pat. No. 4,329,983--Fletcher, a stylette is coupled to a
wire to enable the distal end of the stylette to be pulled into an arc
when inside the lumen of the tube. Whereas the stylette is thin compared
to the tube, the stylette must be bent into a relatively sharper curve in
order to form a relatively more shallow curve in the tube. In U.S. Pat.
Nos. 4,589,410--Miller and 4,150,676--Jackson, pull rings at the proximal
end are tied to the distal end via a wire or the like disposed in a
passage on one side of the tube. Pulling the ring shortens that side of
the tube and increases the bend toward the side. In U.S. Pat. No.
4,685,457--Donenfeld, several wires and passages are provided for bending
the tube in different directions by manipulation using the proximal end of
the tube. In each of these wire-in-passage arrangements, the bend occurs
smoothly along the entire length of the tube toward the side that is
shortened. Thus, the tube is pulled into a tighter arc than the nominal
arc in which the tube is supplied, and accordingly bears laterally against
tissues in the mouth and/or throat.
In certain instances, a smooth bend in the tube is insufficient to guide
the tube into the larynx and trachea. Patients having a small receding
chin (micrognathia), an unusually anterior larynx, or a relatively short,
thick neck may present problems because although the patient's head may be
tilted back, the passage into the larynx still requires a sharp anterior
bend. In certain trauma victims, it may be unwise to tilt the head to
extend the neck for straightening the path of the endotracheal tube.
In U.S. Pat. No. 4,529,400--Scholten, a similar tool is provided for
bending an endotracheal tube. A plurality of articulated links are
arranged in a flexible plastic tube, from an area near a handle at the
proximal end to a link at the distal end. A wire is coupled from the
handle to the endmost distal link. All of the links exclusively pivot in
one direction, but a second link from the distal end is arranged to permit
a pivot in only the opposite direction. Generally, the device pulls the
length of the tool into a tighter curve in one direction only, namely
anteriorly, and the tool bends continuously over its length in a manner
similar to the wire-in-passage devices discussed above. However, the
second link from the distal end cause a diversion in the opposite
direction. Thus, the Scholten tool is useful for nasotracheal intubation
in that the continuous bending of the proximal links applies force to push
the soft palette and epiglottis anteriorly, guiding the tube toward the
larynx in a generally circular bend, whereas the distal link is diverted
posteriorly in an S-shaped bend, such that the distal end of the tube
passes through the vocal cords along a line perpendicular to the extension
of the vocal cords. The device is particularly adapted for nasotracheal
intubation due to its S-shaped bend. The arrangement of links along its
full length is expensive.
Continuously bending tool arrangements generally cannot follow the anatomy
as needed for oral intubation because the tube bends generally along its
length. The tube is supplied in the nominally expected arc of the passage
from mouth to larynx, and it is the distal end of the tube that needs to
bend to pass the larynx generally perpendicular to the vocal cords.
General bending to a shorter radius arc may cause the distal end to move
closer to the direction of tracheal insertion, but may not bring the
distal end into a position needed for passage into particularly anterior
tracheal openings. If the bend is increased, such tools apply force to
portions of the patient's anatomy in a direction laterally of the tube,
and are not fully adequate for guiding the end of the endotracheal tube
into place. It would be advantageous to improve intubation techniques by
providing an intubation assist tool that follows the pattern of the
patient's anatomy rather than applying force, that uses the tube itself as
the insertion device instead of a stylette along which the tube slides,
and that can be diverted at the distal end by a substantial angle as
needed for oral intubation in difficult circumstances. It would also be
advantageous to provide a means to assist in intubation in real time, by
enabling diversion of the end of the tube to a precise angle while under
direct visualization, in a non-cumbersome fashion and without applying
force to surrounding oropharyngeal structures.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an intubation assist tool that
fits closely to the inner diameter of an endotracheal tube such that
bending of the tool produces closely corresponding bending of the tube.
It is another object of the invention to employ a generally rigid
endotracheal tube guide, formed generally into a fixed arc, and that has a
mechanism for manually controlled additional bending exclusively adjacent
the distal end.
It is also an object of the invention to provide an ergonomic oral
intubation assist tool that conforms to the user for operation with one
hand while using the other hand to manipulate a laryngoscope.
It is another object of the invention to provide an intubation assist tool
that is useful for normal and abnormal anatomies, and which is durable and
inexpensive.
It is still another object to manipulate the distal end of an endotracheal
tube to a precisely correct angle in real time (i.e., without withdrawing
the endotracheal tube from the mouth), under direct visualization, thereby
obtaining the full advantage of the dexterity of the operator in placing
such tubes in patients having varying anatomies.
These and other objects are accomplished by a tool that assists in oral
placement of an endotracheal tube in a patient and has an elongated
proximal portion with an internal passage, defining a fixed arc
corresponding to the passage through the mouth to the larynx, i.e.,
arching anteriorly in a medial plane of the patient toward a distal end of
the tool.
In one embodiment of the invention, two links occupy 10-20% (4-5 cm) of the
tool length and are attached to the proximal portion by pivot pins
permitting the links to pivot in the medial plane. A control line, which
can comprise a flexible wire, extends through the proximal portion,
passing anteriorly of the pivot pins, and is attached to the endmost link.
Tension applied to the control line by a lever diverts the links
exclusively anteriorly of the fixed arc, thereby diverting the end of the
endotracheal tube at least 90.degree.-100.degree., for guidance through
the larynx. The proximal portion is nearly as wide as the internal
diameter of the endotracheal tube, which diverts to substantially the same
extent as the links.
In another embodiment, the tool has a single link. The link occupies 10-20%
(4-5 cm) of the tool length. The link is attached to the proximal portion
of the tool by a pivot pin such that the link can pivot in the medial
plane. A control line extends through the proximal portion of the tool,
and preferably comprises an elongated rod such as a solid but flexible
length of stainless steel. The control line attaches anteriorly of the
pivot pin to the link at a pivot coupling. When tension is applied to the
control line by a lever at the proximal end of the tool, the link pivots
anteriorly of the fixed arc, producing a sharp bend at the distal end of
the endotracheal tube and facilitating guidance of the tube through the
larynx and into the trachea. As with the two link embodiment with the wire
control line, the outer diameter of the proximal portion and the link is
nearly as large as the inside diameter of the endotracheal tube. Thus the
tube is diverted to substantially the same extent as the link, e.g.,
approaching 90.degree. relative to a longitudinal axis of the tool
adjacent the distal end.
The intubation assist apparatus is user friendly in that no new skill,
knowledge or dexterity must be learned in order to use it. The
laryngoscope blade and endotracheal tube can be inserted into the mouth in
a conventional manner. Once inserted, and with the intubation assist
apparatus in place, the endotracheal tube and laryngoscope remain in place
and need not be withdrawn for adjustments. The distal end of the
endotracheal tube is controllably diverted by manual action of the
operator in real time, under direct visualization, making it readily
possible to obtain the angle necessary and to negotiate the bend from the
posterior oropharynx into the trachea.
Once the endotracheal tube is properly inserted, the intubation assist
apparatus is readily removed from the tube because upon release of manual
pressure on the control lever by the operator, pressure on the inside of
the endotracheal tube is released, and the intubation assist apparatus
relaxes into the unidirectional bend defined by the endotracheal tube. No
pressure or force need be exerted on the surrounding pharyngeal structures
in order to cause the endotracheal tube and the intubation assist
apparatus therein to negotiate the necessary curve.
BRIEF DESCRIPTION OF THE DRAWINGS
There are shown in the drawings certain exemplary embodiments of the
invention as presently preferred. It should be understood that the
invention is not limited to the embodiments disclosed as examples, and is
capable of variation within the scope of the appended claims. In the
drawings,
FIG. 1 is a perspective view illustrating the tool for assisting in manual
placement of an endotracheal tube in a patient, the tube and the tool
being shown arranged for insertion of the tool into the tube.
FIG. 2 is a partial section view along the medial plane of a human,
demonstrating use of the tool together with a laryngoscope.
FIG. 3 is a perspective view of the tool showing the proximal and distal
end portions, the tool shown cut away between the end portions.
FIG. 4 is a top plan view of a preferred embodiment, showing the alignment
of the handle to the plane in which the elongated portion of the tool
bends.
FIG. 5 is a perspective view illustrating an intermediate link between a
distal link and the elongated portion of the tool.
FIG. 6 is an elevation view along line 6--6 in FIG. 5.
FIG. 7 is a perspective view illustrating the distal link.
FIG. 8 is a section view along lines 8--8 in FIG. 7, with the control line
also being shown.
FIG. 9 is a partial elevation view illustrating an antifriction covering on
the tool.
FIG. 10 is a partial section view illustrating a further embodiment of the
tool according to FIGS. 1-9, having a single movable end segment.
FIG. 11 is an elevation view of another alternative embodiment of the tool,
having a rod and channel structure and one movable segment.
FIG. 12 is an elevation view of the embodiment according to FIG. 11, with
the movable segment shown in its extreme deflected position.
FIG. 13 is an elevation view showing a preferred base member for the tool
according to FIGS. 11 and 12.
FIG. 14 shows side and end elevation views of the movable segment.
FIG. 15 is an elevation view showing an alternative structure for the lever
handle of the tool.
FIG. 16 is a partly cut-away elevation view corresponding to FIG. 11,
showing the movable segment and lever handle positions with the segment
undeflected.
FIG. 17 is a partly cut-away elevation view corresponding to FIG. 12,
showing the movable segment and lever handle positions with the segment
deflected to a maximum of 90.degree..
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A tool 20 for assisting in manual placement of an endotracheal tube 22 in a
patient 26 is shown in FIGS. 1 and 2. Tool 20 is placed inside
endotracheal tube 22 as shown in FIG. 1, being simply slipped into the
lumen of tube 22, where the tool occupies a substantial proportion of the
internal diameter of the tube. For intubation, tube 22 is passed, with
tool 20 therein, along a route through the patient's mouth 32, pharynx 33
and larynx 35, as shown in FIG. 2, preferably with the aid of a
laryngoscope 42 for lifting the tissues of the tongue 43 and enabling
viewing of the area at the rear of the throat in the area of the larynx
35. Tube 22 is advanced through larynx 35 into trachea 44 until an
inflatable cuff 46 passes the vocal cords. By use of tool 20, tube 22 is
diverted anteriorly at its end, to assist in insertion through larynx 35
and into trachea 44.
Tool 20 includes an elongated proximal portion 50 with an internal passage
52 through which a control member 55 passes as described in more detail
below, for controlling bending of tube 22, and more particularly for
forming a relatively sharp anterior bend at a distal end 59 of tube 22
over a limited distance, for example about 1 to 5 cm. In the embodiment of
FIG. 1, proximal portion 50 is a continuous length of relatively rigid
tubing, forming a bend in a fixed arc 62, leading to a distal portion 64
at which an articulated link mechanism 72 is mounted so as to allow
bending of a distal portion of tube 22 anteriorly of the patient as needed
to pass end 59 of endotracheal tube 22 forward of the esophagus 73 and
into trachea 44. Control member 55 in this embodiment is a flexible line
such as a wire or chain, conveying tension to one or more pivotable end
segments to divert the end of the tool.
As shown in FIGS. 1-4, proximal portion 50 defines an arc corresponding to
the route through mouth 32 to the area of larynx 35, and extends
anteriorly in a medial plane 77 of patient 26 toward distal end 64 of tool
20. The fixed arc is thus shaped, and proximal portion 50 is sufficiently
long to position tube 22 adjacent larynx 35. However, a tangent to the
fixed arc may be aligned more to esophagus 73 than trachea 35,
particularly in patients having a very anterior larynx.
At least one articulated link 88, and a plurality of articulated links in
FIGS. 1-4, are pivotally attached to proximal portion 50 at its distal end
82 by a respective pivot pin 84 permitting link 88 to pivot relative to
proximal portion 50 in the patient's medial plane 77 and in particular to
divert distal end 64 of tool 20, and endotracheal tube 22 thereon,
anteriorly by manual action of the user.
Elongated control member 55 extends through the bore or passage 52 along
the length of proximal portion 50. Control member 55 passes anteriorly of
pivot pin 84 and is attached to distal link 88. Accordingly, when tension
is applied to control line 55, distal link 88 is diverted anteriorly
relative to a tangent of fixed arc 62 in medial plane 77, thereby
diverting endotracheal tube 22 for guidance through larynx 35. Distal end
59 of endotracheal tube 22 is diverted anteriorly so as to become aligned
substantially perpendicular to the extension of the vocal cords 89,
whereupon endotracheal tube 22 can be advanced into trachea 44 by further
manual advance of tool 20 and tube 22 thereon.
The distal link portion 64 of tool 20, and preferably both proximal and
distal portions 50, 64 have an outside diameter that is substantial
relative to the inside diameter of tube 22. Accordingly, the arc 62 and a
diversion angle achieved by tool 20 are substantially achieved in tube 22
as well. The outside diameter can be equal to 50 to 90% of an internal
diameter of endotracheal tube 22, typically 2.0 to 9.5 mm, and in
particular 5.5 to 8.5 mm for intubation of an adult. The proximal and
distal portions 50, 64 preferably have an outside diameter approximating
an internal diameter of endotracheal tube 22, with sufficient clearance to
permit free sliding of tool 20 in endotracheal tube 22 for easy withdrawal
of tool 20 after tube 22 has been placed. In this manner, endotracheal
tube 22 is diverted substantially to a same extent as the at least one
link 88.
Tool 20 is preferably only slightly longer than tube 22, which typically is
about 30 cm in length. However, as a means to position distal end 64 of
tool 20 precisely at the distal end of tube 22, a stop ring 92 and
thumbscrew 93 can be provided as shown in FIG. 1. Stop ring 92 can be
positioned as required along proximal portion 50 of tool 20 and locked in
place by tightening thumbscrew 93.
In one embodiment of the invention, shown in FIGS. 1-9, a plurality of
links 88, 102 are provided at distal end 64 of tool 20, attached to
proximal portion 50 by pivot pins 84 coupling links 88, 102 together
serially and with proximal portion 50, and the connecting member comprises
a length of thin flexible wire or the like. Each pivot pin 84 permits a
respective one of links 88, 102 to pivot anteriorly in the medial plane
described by the fixed arc of proximal portion 50.
In FIG. 3, proximal portion 50 is shown cut away to better illustrate
pivoting links 88, 102 at distal end 64 of tool 20 and the details of a
handle 110 whereby tension is applied to control member 55 for diverting
links 88, 102 anteriorly of the arc 62 defined by proximal portion 50.
Links 88, 102 are diverted by tension on control member or line 55 in part
because the control line passes anteriorly of each of the pivot pins 84.
Thus links 88, 102 all pivot in a same direction, namely anteriorly in
medial plane 77, as tension on control line 55 shortens the distance on
the anterior side of tool 20, between proximal portion 50 and the endmost
distal link 88.
The pivoting links 88, 102 extend only over a short distal length, for
causing the end of endotracheal tube 22 to divert toward larynx 35 and
trachea 44. Preferably, the pivoting portion 72 defined by links 88, 102
extends about 10 to 20% of the length of tool 20, which enables a
substantial bend or diversion to be formed at the distal end of tube 22.
Proximal portion 50 is rigidly curved in fixed arc 62 and is not displaced
during diversion of distal links 88, 102. Proximal portion 50 can be
permanently formed into the fixed arc or can be slightly malleable such
that fixed arc 62 can be changed by manually bending proximal portion 50.
Preferably, proximal portion 50 is bendable only with difficulty, if at
all, and consists substantially of an integral rigid tube of stainless
steel or relatively rigid plastic.
Referring to FIGS. 3 and 4, one means for applying tension to control line
55 includes handle means 110 having a base 112 at a proximal end 113 of
proximal section 50 and a lever 114 pivotally mounted on base 112. Control
line 55 is attached to lever 114 for application of tension to control
line 55 by pulling upward (in FIG. 3) on the control line or member
relative to base 112. Base 112 can be a metal block with a hole 116 for
receiving proximal portion 50 via press-fitting, and permitting control
line 55 to pass to a point of attachment 118 on lever 114. Lever 114 in
this embodiment has a paddle portion 122 pivoted to base 112 at a pivot
pin 124 spaced from proximal portion 50. Therefore, by pivoting paddle
portion 122 toward the base or toward proximal portion 50, point of
attachment 118 of control line 55 is lifted, applying tension to the
control line and diverting distal links 88, 102.
In FIG. 4, proximal portion 50 and its fixed arc or bend 62, and also the
pivot path of links 88, 102, each reside in a horizontal plane, which is
the medial plane of patient 26 when tool 20 is in use. However, the plane
125 including paddle portion 122 of lever 114 is angled approximately 15%
relative to the medial plane. This is an ergonomic arrangement for manual
handling of tool 20. In FIG. 4, paddle 122 is angled about 15.degree.
downward or clockwise from the medial plane, which is comfortable for a
user who manipulates tool 20 with his or her right hand. Paddle 122 can be
angled in the opposite direction for persons who prefer to manipulate tool
20 with the left hand, e.g., left-handed people or right handed people who
prefer to use the right hand to manipulate laryngoscope 42 as in FIG. 2.
As best shown in FIG. 3, lever 114 has an L-shape, with paddle portion 122
and a base leg 126 forming the L-shape. Lever pivot pin 124 extends
through base leg 126 at a point spaced from internal passage 52 of
proximal portion 50 and control line 55 being attached to base leg 126.
The lever can be arranged such that paddle portion 122 and base leg 126
are perpendicular (i.e., with the paddle portion parallel to proximal
portion 50 at rest), or for additional clearance the paddle portion can be
over 90.degree. relative to the base leg to allow a greater range of
movement of the lever until paddle 122 contacts proximal portion 50.
FIG. 3 also shows stop 92 on proximal portion 50 and thumbscrew 93 or
similar means provided for adjusting and fixing stop 92 at a desired
longitudinal position along proximal portion 50. Stop 92 is wider than the
internal diameter of tube 22, and when tube 22 is pushed upwardly against
stop 92, e.g., as shown in FIG. 2, the pivotal links 88, 102 at the distal
end of endotracheal tube 22 reside inside tube 22 closely adjacent the end
tube 22. Tool 20 thus remains inside tube 22, but is operative to divert
the end of tube 22 anteriorly. For a shorter tube 22, stop 92 is adjusted
downwardly, etc.
FIGS. 3-8 illustrate aspects of preferred pivotal links 88, 102 at distal
end 64 of tool 20. At least one link is articulated at distal end 64, and
preferably a plurality of links are provided, extending four or five
centimeters from the extreme distal end. Links 88, 102 are articulated via
pivot pins formed by screws 132, providing a durable arrangement that
allows the user to exert the necessary pressure on tube 22 from inside,
along a limited length at distal end 64. Two links are provided in the
preferred arrangement shown. A more proximal intermediate link 102 is
attached to proximal portion 50 at its distal end by a first pivot pin 84.
An endmost distal link 88 is attached to the proximal or intermediate link
102 by a second pivot pin 84, parallel to the first pivot pin. Whereas the
nature of the respective articulation joints is the same, the same
reference numbers are used to identify corresponding parts of each.
Control line 55 passes on an anterior side of each of the first and second
pivot pins 84.
FIG. 5 shows a preferred arrangement of intermediate or proximal link 102.
First end 142 of proximal link 102 has a narrowed shape due to chordal
flattening on opposite lateral sides for a distance adjacent first end
142, parallel to the medial plane. As shown in FIG. 1, a clevis or
U-shaped slot 144 in a lower end of proximal portion 50 receives the
narrowed first end 142 of proximal link 102. The clevis 144 has a
depression 146 such as a counterbore (for a machine screw) or countersink
(for a flat head screw) for receiving the screw 132 that functions as
pivot pin 84. The screw head lies flat on one side of clevis 144 and
engages a threaded hole 148 on the other side. A through bore 152 in first
end 142 of link 102 allows screw 132 to pass through and enables link 102
to pivot. Distal link 88 similarly has a narrowed end 142 for engaging a
clevis 144 in the more proximal link 102.
Preferably, clearance is provided for control member 55, in this case a
flexible line, in a manner that permits the line 55 to become displaced
from pivot pin 84 when link 88 or 102 is diverted. Control line 55 passes
through an off-center longitudinal bore 154 through a body of link 102, as
shown in FIG. 6. A lateral slot 156 communicating with off-center bore 154
extends toward the adjacent link 88 along the anterior side of male end
142 of each of the clevis fittings. On the female ends of the clevis
fittings, the U-shaped slot 144 can be made slightly longer longitudinally
than is needed for clearance with the corresponding male end 142 of the
adjacent part of the clevis fitting, also providing clearance for control
line 50. The result is illustrated in FIG. 1. When links 88, 102 are
diverted by tension on control line 55, clearance provided by lateral
slots 156, and preferably also by the depth of U-shaped slots 144, permit
control line 55 to move anteriorly. A sharp distal bend or diversion is
thus obtained at the end 64 or tool 20, and in tube 22 carried thereon.
Referring to FIG. 7, distal link 88 preferably articulates on intermediate
link 102 via the same form of structure as used for articulating
intermediate link 102 to proximal portion 50. However, control line 55
attaches to distal link 88 at a point spaced longitudinally from pivot pin
bore 152, rather than movably passing through an off-center bore 154 as
with link 102. In the embodiment shown, a first longitudinally-inclined
transverse bore 164 is provided at an end of lateral slot 156 of link 88.
A set screw 166 (shown in FIG. 1 but not FIG. 8) engages control line 55
in transverse bore 164 to affix control member 55 to distal link 88.
Preferably, a second transverse bore 168 inclined in an opposite
longitudinal direction is provided with a similar set screw means for
attaching the extreme end of the control line to distal link. Second bore
168 and its set screw 166 provide additional security of connection. Due
to the passage of control line 55 around an angle between the transverse
bores, control line 55 is affixed securely and permanently. A shallow slot
169 can be provided in a surface of link 88 between transverse bores 164,
168, such that control member 55 remains inside the outer contour of
distal link 88. Control member 55 can be attached to handle lever 114 in
the same manner.
In the exemplary embodiment shown, and for an adult size endotracheal tube,
links 88, 102 and proximal portion 50 are about 5 mm in diameter, or 0.6
to 0.75 of the internal diameter of tube 22. Intermediate link 102 is
about 3 cm long; distal link 88 is about 2.3 cm; lateral slot 156 is about
1 cm long; and U-shaped slots 144 of the clevis fittings are about 2 mm
deeper (longitudinally) than needed for clearance with narrowed ends 142.
According to these dimensions, the two serially coupled links 88, 102 can
divert endotracheal tube 22 from a neutral position along a tangent of
fixed arc 62 to a diverted position wherein the extreme end of
endotracheal tube 22 is angled at least 90.degree. to 100.degree. anterior
of said tangent.
Another embodiment of the invention is shown in FIGS. 10-17, using the same
reference numbers to identify corresponding structural parts. In the
embodiment shown in FIG. 10, a single distal link 88 is provided at distal
end 64 of tool 20, attached to proximal portion 50 by pivot pin 84
coupling distal link 88 with proximal portion 50, and the tool can
otherwise be as described above. Pivot pin 84 permits distal link 88 to
pivot anteriorly in medial plane 77 relative to proximal portion 50. This
bends the tube exclusively at the distal end, and proximal portion 50
remains fixed in shape.
In a preferred embodiment shown in FIGS. 10-17, control member 55 comprises
a solid elongated rod of stainless steel or the like, received in a
channel along proximal portion 50 and attached to the lever handle at one
end and to link 88 at the other end. The pivot axis of the connection
between link 88 and control member or rod 55 is laterally displaced from
the pivot axis of pin 84, connecting link 88 to proximal member 50.
Therefore, from an undiverted position as shown in FIG. 11, tension on
control rod 55 applied by handle 110 causes link 88 to divert as shown in
FIG. 12.
Proximal portion 50 in this embodiment is rigid as in FIGS. 1-10, but is
shown substantially straight. The proximal portion 50 could also be
somewhat curved, however the pivoting connection with handle 110 is such
that longitudinal displacement of control rod 55 relative to proximal
portion 50 causes lateral displacement of rod 55 upwardly or downwardly in
the channel along the side of proximal portion 50, particularly near
handle 110. Control member 55 is threaded at the handle end and coupled to
a threaded cylindrical plug in a bore in the handle. As shown in FIG. 13,
the stationary base of handle 110 has a clearance opening 182 permitting
longitudinal and lateral movement of control member 55 therein.
The laterally spaced pivot connections between link 88 and proximal portion
50 as well as control rod 55, can be made using screws, press-fit pins or
rivets (not shown). FIG. 14 shows the shape of link 88 in side view as in
FIGS. 11 and 12, and in a top view. Link 88 is generally cylindrical with
a rounded distal end and a proximal end having a slot receiving the
narrowed ends of members 50 and 55. The pivot pins are fixed in laterally
spaced transverse holes in the slotted end, passing through clearance
holes in members 50, 55 for pivoting.
An alternative form of lever for handle 110 is shown in FIG. 15, and
employs finger openings instead of a straight lever handle as in FIGS. 11
and 12. The finger openings can include a closed ring enabling the
operator to exert tension to divert link 88 or compression to bring link
88 back into alignment with proximal portion 50. However, in general the
endotracheal tube 22 (see FIGS. 1 and 2), which is relatively thick and
springy to avoid pinching off the lumen of the tube, tends to urge link 88
toward a position of alignment with proximal portion 50.
The embodiment of FIGS. 11-17 is more durable than an arrangement in which
control member 55 is a flexible wire. A flexible wire control line is
subject to metal fatigue at the connections with handle 110 and link 88,
where the wire is repeatedly flexed in using the tool. A flexible wire as
in the embodiments of FIGS. 1-10 also has a tendency to wear against the
inside edges of proximal member 50 and link(s) 88. The embodiment of FIGS.
11-17 does not suffer from this type of wear.
Distal link 88 extends only over a short distal length, for causing the end
of endotracheal tube 22 to divert toward larynx 35 and trachea 44. In
FIGS. 11-17, for example, link 88 can be about 6 mm (0.25 inch) in
diameter. Link 88 can be diverted from a position of alignment with
proximal portion 50 (FIG. 16) to about 90.degree. diversion (FIG. 17) by
diverting the lever handle by about 8.degree.. Preferably, distal link 88
extends only a limited distance along the length of tool 20, protruding
for example by 13 mm (0.5 inch) in FIG. 17. This allows a substantial
controllable bend or diversion to be formed at the distal end of tube 22,
particularly because the tool occupies a large part of the internal
diameter of tube 22.
In the exemplary embodiment shown, and for an adult size endotracheal tube,
distal link 88 and proximal portion 50 are about 5 mm in diameter, or 0.6
to 0.75 of the internal diameter of tube 22. Distal link 88 is about 5 cm;
and the U-shaped slot 144 on the distal end is about 2 mm deeper
(longitudinally) than needed for clearance with narrowed end 142 of distal
link 88. According to these dimensions, distal link 88 can divert
endotracheal tube 22 from a neutral aligned position to a diverted
position wherein the extreme end of endotracheal tube 22 is angled by
substantially 90.degree. anteriorly of the longitudinal axis of proximal
portion 50.
Both of the above embodiments are very effective for inserting tube 22
through larynx 35, and are effective even for patients having potential
problem anatomies or conditions, such as an unusually anterior larynx,
short chin or trauma that limits freedom to tilt back the head. Of course
other specific dimensions and specific articulation structures are also
possible.
Proximal portion 50 and the link or links 88 define a generally smooth
cylindrical outer contour. The respective parts are preferably made of a
surgical stainless steel. An antifriction covering such as
polytetrafluoroethylene (Teflon) can be provided as shown in FIG. 9, or
the parts can be bare stainless steel as appropriate for autoclaving.
It is possible to include a spring (not shown) providing a bias tending to
urge the lever handle in a direction opposite the direction that places
tension on control member 55. For example, a compression spring can urge
the paddle 122 of lever handle 112 outwardly from handle base 112, opposed
by the user's grasp. However, it has been found that the inherent
stiffness of endotracheal tube 22 is sufficient to provide a return force
for bringing links 88, 102 back to their rest position when tension on
control line 55 is released, and allowing tool 20 to be withdrawn quickly
and easily from tube 22.
The dimensions of tool 20, the angle to which links 88, 102 can be diverted
and other aspects of the invention can be varied as needed for particular
circumstances, e.g., smaller or larger tracheal tubes and/or patients, use
for patients having a normal-anatomy vs. an unusually anterior larynx. The
invention is convenient and useful with normal anatomies, as well as being
particularly useful for those anatomies in which intubation problems are
otherwise encountered.
The invention having been disclosed in connection with the foregoing
variations and examples, additional variations will now be apparent to
persons skilled in the art. The invention is not intended to be limited to
the variations specifically mentioned, and accordingly reference should be
made to the appended claims rather than the foregoing discussion of
preferred examples, to assess the scope of the invention in which
exclusive rights are claimed.
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